A Novel Bearing Swivel Joint and a Universal Joint for Concrete Pull-Off Testing Using a Material Testing Machine

The overall goal of this short study was to integrate two pull-off coupling devices for concrete: a bearing swivel joint and a universal joint, into an existing material testing machine. Their performance was evaluated in terms of efficiency using setup duration and compared to that of a commercially available portable testing device. Fifty-three pull-off tests were conducted on concrete prisms in accordance with ASTM C1583-04. Our results indicate that the portable tester was most efficient (6 min/test), followed by the universal joint (16 min/test), and then the bearing swivel joint (22 min/test). An online movie, as referenced in the text, demonstrates the modified test procedure, and recommendations for improvements to the test method are briefly discussed. Future testing will evaluate the variability among test results from the three devices.